1. Field of the Invention
This invention relates to a selective switch, more particularly to a selective switch which has a unitary spring member for rapid change between two different connecting states.
2. Description of the Related Art
Selective switches are usually employed in electric appliances to control the operation of the latter in two different operating states. Referring to FIG. 1, a conventional selective switch is shown to include a button cap 10 which is mounted on a switch housing and which has an annular flange to form a receiving space 16. A rigid rod 11 is received in the receiving space 16 and extends downward for coupling with a contact plate 12. The contact plate 12 can be driven by the rod 11 to move between a first position in which the contact plate 12 is in contact with first and second conductive members 13, 14 in response to depression of one side of the button cap 10, and a second position in which the contact plate 12 is in contact with first and third conductive members 13, 15 in response to depression of the other side of the button cap 10. A spring 17 surrounds tightly the rigid rod 11 and biases the contact plate 12 for contact with appropriate ones of the conductive members 13, 14, 15. The drawbacks of the conventional selective switch are as follows:
1. A strong pushing force must be applied on the button cap 10 when changing switching states since the rigid rod 11 is used to move the contact plate 12. Moreover, the switching action is relatively slow. PA1 2. A clearance is formed between the contact plate 12 and the conductive members 14, 15 during movement of the contact plate 12 between the first and second positions, thereby resulting in an electric arc which can burn down and destroy the selective switch. PA1 3. The size of the selective switch cannot be reduced because of the presence of the rigid rod 11.